The serial number of an engine will tell you many things you need to know about the vehicle it is a part of. Although you should consider many other things when you purchase a vehicle, you should learn everything you can about the engine. This becomes increasingly important when the vehicle you want to buy is one that has had aftermarket work done on it, such as a new engine dropped in. Then it becomes critical that you find the serial number of the engine so you can research the car properly.
Check the obviously visible locations on your engine to see if you can spot a serial number. Open the bonnet and look at the engine without taking anything off or apart, and try to spot the number. Most serial numbers are a long combination of letters and numbers. They may be scribed directly onto the engine block, or may be on a small plate attached to the block.
Remove the plastic cover from the top of the engine if your engine has one. Even on some engines with a cover, the number may be visible with it in place. However, if you cannot see it with the cover on, remove it. Now, see if the serial number is stamped clearly on any of the areas that were hidden by the cover.
Use a rag to wipe away dirt and grime that might be obscuring a serial number. Usually, checking serial numbers is more important on older vehicles, and the engines in these vehicles can become dirty with grease and oil over the years.
Check these common locations for the serial number if you haven't found it. Check behind the distributor cap or just forward of the passenger side cylinder head. Small block Chevy engines have their codes in these locations. Early Fords often had no engine serial number. Instead, a vehicle serial number was stamped on the bell housing of the transmission. On Mopar engines, the serial number is commonly behind the distributor cap or under the cylinder head, and can appear on either side of the engine depending on the model.